Syringe.



MCELR v SYRINGE. I I APPLICATION FILED APR. 12, I915- 1,,165,686. I Patented Dec. 28, 1915.

7 va/ Ix El /7 12' PATRICK J'. MCELBUY, 0F GAMBEEDGE, 1/1..

CHARLES P. BLINILI, JR., 013 BOSTON, I'fl' SETIS, ASE-16110113 OF ONE-HALF TO JSETTS, ANT!) R JTUN YVHIDDEN, OF

BROOKLZNE, ll'IASSACI-iUSETlS, RECEIVERS OF RANDALL FAICHNEY CO.

SYRINGE.

Application filed April 1.2, 1915.

Z 0 all to from it may concern Be it known that 1, PATRICK J. Molinnor, a citizen of the Unite l States, and a resident of Cambridge, in the county of Middlesex and State of ll lassachuse ts, have invented certain new and useful Improvements in Syringes, of which the following is a. specification.

This invention relates particularly to small syringes for hypodermic use, comprising a. barrel or container usually of glass having a contracted outlet at one end adapted to engage a hypodermic needle, its other end being open, and a piston comprising an elongated cylindrical stem of smaller diameter than the interior of the barrel, and compressible material engaged with the inner end of the stem and constituting compressible head which conforms closely to and is in slidingcontact with the internal surface of the barrel or container.

The invention has for its object to pro vide certain improvements in the form and construction of the inner end portion of the stem and of the compressible head ngaged therewith, whereby the head may be readily and securely engaged with the stem and caused to turn therewith in the barrel.

lfhe invention consists in the improvements which 1 will now proceed to describe and claim.

Of the accompanying drawings forming a part of this specification: Figure 1 is a side elevation of the stem, and a longitudinal section of the head, of a piston embody ing my invention, the barrel being shown in section; Fig. 2 represents a side View of a portion of the stem; Fig. 3 represents an end View showing the inner end face of the stem; Fig. 1 represents a sectional View of the head, detached and contracted to substantially its normal size; Figs. 6, and 7 represent views corresponcing respectively to Figs. 2, 3 and 1, and illustrating a modification.

The same reference characters indicate the same or similar parts in all the Views.

in the drawings, 12 represents the stem and 13 the head of a syringe piston, said stem and head being movable in a syringe barrel or container 14-.

The stem may be made of glass or any other suitable material and may be of metal, if desired. T he stem is of cylindrical form Specification of Letters Patent.

Patented Dec. 28, 1915.

Serial No. 28,622.

and its inner end is formed substantially at right angles with its longitudinal. axis, and constitutes what 1 call an inner end face 15. The diameter of the stem is reduced to form an annular shoulder 16, separated from the end face 15 by a narrow peripheral portion 17, and facing oppositely from the end face 15.

lhe reduced portion 12 of the stem is adapted to be embraced by the sleeve hereinafter described, and therefore constitutes a sleeve-engaging portion.

The head 13 may be made of any suitable compressible material s ch as asbestos, and formed from an asbestos cord wound and disposed on the stem substantially according to the disclosure in my Patents 319,918 and 962,65? to cover the end face 15, the peripheral portion 17 and form a sleeve portion engaging the shoulder 16. I prefer, however, to mold the head from elastic rubber or its equivalent, said head being elastically yielding and compressible. The head includes a body portion 1S extending across and covering the end face 15, and an annular marginal portion 13 surrounding the peripheral portion 17 or" the stem and compressed between the said portion and the interior of the barrel.

On the marginal portion 13 is formed a sleeve 18 which is internally contracted to embrace the stem portion and form an internal shoulder 19, adapted to engage the stem shoulder 16. 'l he head and sleeve constitute a cup adapted to receive the end face 15 and the adjacent portions of the stem, as shown by 1, the body portion 13 of the head covering the end face 15, and being held said face by the engagement of the internal shoulder 19 with the stem shoulder 16, the stem and head being thus connected for simultaneous longitudinal movement.

Sometimes a sticky liquid is administered by a syringe of this character, in which case the head, which conforms closely to, and is compressed by the internal surface of the barrel, becomes cemented more or less firmly to the barrel by said liquid, after protracted disuse of the syringe while it contains the liquid, so that considerable force is required to free the head and permit it to slide in the barrel. The easiest and best way of freeing the head is by turning it in the barrel, by

turning the stem. If endwise pressure is exerted on the stem to free the head, the pressure is liable to break the barrel. To prevent the stem from turning in the head without turning the latter, and to insure the rotation of the head by the stem Without liability of injuring the marginal portion 13 by the twisting strain exerted on the head by the stem, 1 provide the end face 15 with spurs 21, formed to indent the inner surface of the body portion 13, and thus cause said body portion and the marginal portion to turn with the stem. Said spurs are preferably pointed and of pyramidal form although they may be of conical or other form, if desired. The peripheral portion 17 is preferably provided with similar spurs 22 radiating therefrom and formed to indent the inner surface of the marginal portion 13 of the head. The spurs 22, however, unaided by the end face spurs 21, cannot be relied upon to free the head, because they are liable to turn in the marginal portion of the head, without turning the head. l have found that the end face spurs 2-1, either alone or in cooperation with the peripheral spurs 22, constitute a satisfactory and eifee tive means for causing the head to turn with the stem without injurious twisting strain. The reduced portion 12 of the stem adjacent to the shoulder 16, is also preferably provided with spurs 24 formed to indent the inner surface of the sleeve 18 and aid in causing the head to turn as a whole with the stem.

Figs. 5, 6 and 7 illustrate a modification in which the sleeve portion 18 of the head is relatively short, and is provided with an iiiternal annular shoulder 19 adapted to ena shoulder 16 on the stem, the peripheral spurs 22 and 2% being omitted. The stem may be provided with transverse orifices 27 to receive stitches attaching the head to the stem, said orifices being indicated by dotted lines in Figs. 5 and 6.

I claim:

1. A syringe piston comprising astem having an end face at its inner end, spurs projecting outwardly from said end face, head-engaging means adjacent to said face, and a sleeveengaging portion adjacent to said head-engaging means, and an elastic head including a body portion covering said face, a marginal portion embracing a portion of the periphery of the stem and a sleeve incense embracing said sleeve engaging portion, whereby the body portion of the head is held in engagement with said spurs, to cause the head to turn with the stem. 7

2. A syringe piston comprising a stein having an end face at its inner end, spurs projecting outwardly from said end face, head-engaging means adjacent to said face, and a sleeve-engaging portion adjacent to said head-engaging means, and an elastic head including a body portion covering said face, a marginal portion embracing a portion of the periphery of the stem and a sleeve embracing said sleeve engaging portion, whereby the body portion of the head is held in engagement with said spurs, to cause the head to turn with the stem, the stem being provided also with peripheral spurs engaging the internal surface of the marginal portion of the head,

3. A syringe piston comprising a stem having an end face at its inn r end, spurs projecting outwardly from said end face, head-engaging means adjacent to said face, and a sleeve-engaging portion adjacent to said head-engaging means, and an elastic head including a body portion covering said face, a marginal portion enrracing a portion of the periphery of the stem and a sleeve embracing said sleeve engaging portion, whereby the body portion ofthe head is held in engagement with said spurs, to cause the head to turn with the stem, the stem being provided also with peripheral spurs engaging the internal surface of the marginal portion of the head, and with other peripheral spurs engaging the internal surface of said sleeve.

t. A syringe piston stem having an end face at its inner end, head-engaging spurs projecting outwardly from said end face and complemental head-engaging means adjacent to said face, and. adapted to hold a compressible head against said spurs.

5. A syringe piston stem havingan end face at its inner end, head-engaging spurs projecting outwardly from said end face and complemental head-engaging 1821118 adjacent to said face, and adapted to hold a compressible head against said spurs, said stem being also provided with radial spurs to engage other parts of said compressible head.

in testimony whereof I have affixed my signature.

PATRICK J. MCELROY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents Washington, D. C. 

